Automatic firearm assembly



.lune 6, 1967 T. LFFLER 3,323,245

' AUTOMATIC FIREARM ASSEMBLY Filed Oct. 26, 1965 2 Sheets-Sheet l 2Sheets-Sheet 2 Filed Oct. 26, 1965 United States Patent 3,323,246AUTOMATIC FIREARM ASSEMBLY Theodor Liiler, Mulllieim, Baden, Germany,assignor to Rheinmetall GmbH, Dusseldorf', Germany, a German companyFiled (ict. 26, 1965, Ser. No. 505,269 Claims priority, applicationGermany, Oct. 29, 1964, R 39,129 1f) Claims. (Cl. 42-75) ABSTRACT 01TTHE DISCLOSURE A system of semiautomatic and automatic firearms areassembled from a plurality of basic structural units adaptable to morethan one assembly configuration.

This invention relates to automatic firearms and, more particularly, tosuch firearms including a plurality of structural units including acasing, a stock adapted to be removed from the casing, and a connectingelement such as a trigger box detachable from the casing and stock andequipped with a grip.

lt is an object of this invention to provide automatic firearms whichcan be assembled from a plurality of structural units and which are ofsimple and economical manufacture, of comparatively low weight and whichcan be assembled without complicated production equipment. An additionalobject of this invention is to render possible simple and rapid assemblyand repair, -as for example, of damaged or worn-out structural units,especially under emergency conditions, if required.

According to the present invention, the basic body of an automaticfirearm consists of a total of four stmctural units, namely a barrelwith a locking piece, a casing proper, a stock, and a connectingelement. The barrel and locking piece, casing and stock units areconnected to one another by means of tie rods, with the connectingelement being used as an additional connecting element for the otherthree structural units.

In order to reduce the cost of construction and save weight, the tierods can also be used, with advantage, as guide elements, for example,for the breech mechanism of the firearm.

In accordance with a subsidiary feature of this invention, aconsiderable saving in Weight is obtained when the casing consists of ashell part of light construction, such as of light metals, reinforcedplastics or the like, with the structural elements which are actuallyload-bearing or stressed, such as, for example, guides for breechmechanism members, distance rings for the tie rods or the like, securedin the shell part as by casting or by being moldedin during injectionmolding of the shell part.

According to another subsidiary feature of the invention, and in orderto obtain a connection of the aboveenumerated structural units which isfree from play, a resilient element, for example a bent or corrugatedplate spring acting in the axial direction, is arranged between thestock and the casing. This plate spring preferably has its externalcontours adapted to the connection crosssection of the casing and/or ofthe stock. To simplify assembly as a whole, the resilient element mayalso be of annular form and be located in the region of the tie rodswith guides open on one side. The resilient element also serves tocompensate for shrinkage occurring on the injection molding or drawingof the plastics shell for the casing, etc.

In order to accommodate modification of the firearm to a somewhatdifferent function, the connecting element may be either of twomechanisms. More particularly, that 3,323,246 Patented June 6, 1967 ICCelement may be a magazine box and handgrip or may be a belt feedmechanism. The latter mechanism, which is suitably designed for thispurpose, is installed after rotation of the barrel with locking pieceand casing through about the longitudinal axis of the firearm, i.e. intoan inverted position, when it is desired to use the firearm as a machinegun for belted ammunition.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds when taken in connectionwith the accompanying drawings, in which- FIGURE 1 is an explodedperspective view of a firearm comprising four structural units, inaccordance with this invention;

FIGURE 2 is a perspective View of a modified form of the firearm ofFIGURE 1;

FIGURE 3 is a perspective view partly in section of a portion of thefirearm of FIGURE 1;

FIGURE 4 is a view similar to FIGURE 1, of a modified form of firearm inaccordance with this invention;

FIGURE 5 shows a detail of a belt feed associated with a firearm of thisinvention; and

FIGURE 6 shows a modified form of a grip with a trigger box.

Referring now more particularly to the drawings, a firearm is shown inFIGURE 1 which has a barrel 1 with a chamber 2. Secured to the barrel isa locking piece 3 for the breech mechanism, and a hand guard 4. Two tierods 5, 6 are screwed to the locking piece 3, are preferably tubular forreasons of light construction, and are provided with annular grooves 7and 8, respectively, at their ends. The firearm also includes a casingproper 9 and a stock 10.

Assembly of the above-mentioned structural elements is effected by thecasing 9 being positioned encircling and being pushed along the tie rods5, 6 in the direction of the parts 1 to 4, i.e. on to the barrel andlocking piece group, by means of corresponding guide grooves 5 in thecasing. Tight clamping of these two structural units is effected at theend of this operation by means of a retaining bolt 11 which has lockingrecesses 12, 13 for engaging annular grooves 7 and 8, respectively, inthe tie rods. Prior to such insertion, a corrugated or bent plate spring14 which is provided with guides 15' open on one side and encircling thetie rods 5, 6 is also pushed on. Thereafter, a groove or notch (notshown) in the region of the upper front end of the stock 10, facing thecasing, is placed over a hook-shaped extension 1S of the retaining bolt11 to hold the stock in position.

The fourth structural unit or connecting element, preferably consistingof a trigger box 16 with a grip 17 and which forms a single unit with amagazine shaft indicated at 18 when the firearm is to be assembled as anassault rifle, can then be used as an additional connecting element forthe other three structural units. To this end, the parts are connectedto one another by means of pins inserted into holes 19 to 22. The bentor corrugated plate spring 14, which can be stressed wtihout difficultyby the lever effect connection of the stock, insures play-freeconnection of the individual structural groups with one another.Likewise, differences in the longitudinal direction are compensated bythe spring 14,

Instead of the two tie rods shown in FIGURE 1, it is Within the scope ofthis invention to employ several tie rods, for instance four, asillustrated in FIGURES 2 and 3. In order to secure exact fixing of thetie rods in the casing, distance rings 23 may be provided, these beingfixed to the casing for example by being injection-molded integrallywith the shell of the casing. It is also possible to provide specialguides for the breech mechanism or For reasons of weight saving, thecasing 9 is preferably formed by a light weight type of construction(for exf ample with a honeycomb structure) or from profiled tubing,using light ymaterials such as light metals, plastics reinforced withglass iiber or plastic reinforced in another Way. The structuralelements which are actually load-bearing or stressed, such as the guidesfor breech mechanism elements, distance rings forthe tie rods and othersupports, etc., are bedded in the casing as by being cast or injectionmolded integrally therewith.

FIGURE 2 shows a modified form of the locking piece and barrelstructural unit` wherein the chamber 2' is not a component part of thebarrel 1, as is customary,- buty instead is a component partof thelocking piece 3. rl`he barrel 1', locking piece chamber 3 and chamber 2'are connected in this construction by Ameans of a coupling nut 26. Thisarrangementpermits interchange of only that part ofthe barrel which issimpler to produce and subjected to the greatest wear, namely the inneror rifled tube. Furthermore, this arrangement is also advantageousbecause the chamber can now be hardened together with the locking piece.

The line of division between the barrel 1 and the chamber 2 isadvantageously located in the zone of free iiight of the bullet, i.e.about 1 to 2 mm. in front of the socalled cartridge mouth. This line ofdivision may also be f used with advantage for the tapping off of gasfor operating the breech mechanism.

The grip 17 in the lower part of FIGURE 1 is preferf ably a stampedsheet-metal part. The trigger system is units assembled in a modied formof itearm after having been turned through 186 about the longitudinalaxis of the barrel. Thus, the firearm may now be regarded as being in aninverted position. However, the `connecting element assembling thebarrel and locking piece and the casing is now no longer a magazine boxand handgrip as in FIGURE 1, but is a belt feed mechanism 27; so thatwith the same basic components the firearm is now suit- -able for use asa machine gun instead of as an assault rie as in FIGURE 1. FIGURE 6illustrates another design of a trigger box 2S with grip 29, connectionto the casing 9 being effected, first, by means of a tongue and Cilgroove joint 29', 3i) and, second, by means of an insertion joint 31,32.

In the drawings and specification there has been set forth a preferredrembodiment of the invention` and, although speciiic terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation, they scope of the invention being deiined in theclaims:

What is claimed is:

1. An automatic firearm `assembly including a barrel with a lockingpiece, a casing7 a stock, and a connecting element `and comprising meanssecured to said locking piece and extending through said casing forsecuring said barrel, said casing and said stock together, and means onsaid connecting element for securing the same to said locking piece andto said casing and stock.

2. An assembly las claimed in claim'l wherein said means secured to saidlocking piece is a plurality of tie rods.

3. An assembly as claimed in claim 2 wherein said tie rods are tubularand define a means for guiding a breech mechanism for thefirearm.

4. Anassernbly as claimed in claim 2 wherein the free ends of said tierods have means for receiving a retaining bolt for maintaining said`casing assembled With-said bar-` rel and locking piece.

5. An assembly as claimed in claim 1 further comprising resilient meansinterposed between. said casing and said stock for providing a biasingforce axially of the assembly.

' 6. Any assembly as -claimed in .claim 5 wherein said resilient meansis a substantially planar spring member having an outside contourapproximating that of said casing and said stock at their pointofjuncture.`

'7. An assembly as .claimed in claim 6 whereinl said spring member isannular and encircles said means secured to said locking piece. 1

8. An assembly as. claimed iny claim 1. wherein said locking pieceincludes a projectile shell case receiving chamber and is separablefromsaid barrel.

9. An assembly as claimed in claim 1 wherein said connecting element isa magazine box and handgrip and is adapted to contain a triggerassembly.

10. An assembly as claimed in claim 1 wherein said connecting element isa belt feed mechanism.

No references cited.

SAMUEL W. ENGLE, Primary Examiner.

BENJAMIN A. BORCHELT, Examiner.

1. AN AUTOMATIC FIREARM ASSEMBLY INCLUDING A BARREL WITH A LOCKINGPIECE, A CASING, A STOCK, AND A CONNECTING ELEMENT AND COMPRISING MENSSECURED TO SAID LOCKING PIECE AND EXTENDING THROUGH SAID CASING FORSECURING SAID BARREL, SAID CASING AND SAID STOCK TOGETHER, AND MEANS ONSAID CONNECTING ELEMENT FOR SECURING THE SAME TO SAID LOCKING PIECE ANDTO SAID CASING AND STOCK.